Following the notation of [1]} I introduce \(f_u[n_p,n_n]\)  – the condensation energy density, which is a functional of the SF densities \(n_\alpha \) .
Adopting also the notation from [2]} I introduce the condensation energy via the GL expansion
\(\nonumber && \!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!\!f_u=a_p|\psi _p|^2+a_n|\psi _n|^2\\ && +\frac{b_{p}}{2}|\psi _p|^4+\frac{b_{n}}{2}|\psi _n|^4+b_{np}|\psi _p|^2|\psi _n|^2.\) 
